The present invention relates generally to an open-end spinning apparatus and, more particularly, to a fiber guide device for connecting a sliver opening device with a rotor spinning housing in an open-end spinning apparatus.
Open-end spinning apparatus are well known within the textile industry as disclosed in numerous publications. For example, German Patent Publications DE 28 00 795 A1 or DE 195 11 084 A1 describe open-end spinning apparatus with sliver opening devices in which a sliver intermediately stored in a sliver can is presented to a rotating opening cylinder which opens the sliver into individual fibers. The individual fibers are subsequently supplied via a one-piece fiber guide conduit to a spinning rotor rotating in a rotor housing at a high speed wherein the fibers are twisted in an internal rotor groove continuously onto the end of a yarn leaving the spinning rotor via a withdrawal device. The finished yarn is subsequently wound at an associated spooling or winding device into a cross-wound bobbin.
Significant requirements are placed on the design of the fiber guide conduit in which the individual fibers are transported from the opening cylinder to the spinning rotor, e.g. as regards the geometric design or the surface quality. That is, the flow conditions inside the fiber guide conduit must assure that the fibers are held stretched or are stretched during transport. Moreover, the surface of this component must be smooth throughout in order that no fibers can settle or become clogged during the pneumatic transport of the fibers. It should also be avoided that damaging air vortices develop in the boundary layer area of the fiber guide conduit.
The fiber guide conduit devices are made of sheet steel parts both in the open-end spinning apparatus described in German Patent Publication DE 28 00 795 A1 and in the open-end spinning apparatus according to German Patent Publication DE 195 11 084 A1. German Patent Publication DE 23 64 261 A1 also shows similar fiber guide conduit devices made of steel sheeting.
German Patent Publication DE 28 00 795 A1 discloses the manufacture of a fiber guide conduit device by initially fabricating the device from a steel sheet. Then liquid aluminum, for example, is subsequently cast around this prefabricated component in a diecasting tool with an inner form designed as an opening-cylinder housing.
However, such a manufacturing method has not been accepted in practice since it has not been possible to solve satisfactorily certain problems which occur. It developed, for example, that the fiber guide conduit device prefabricated from the steel sheeting may deform in the diecasting tool due to the high pressure and must therefore be specially supported during the process, which is expensive. Moreover, there is the constant danger that liquid casting material may penetrate into the fiber conduit, which has a very negative effect on its surface quality.
According to German Patent Publication DE 195 11 084 A1, the fiber guide conduit device is also designed as a cold-formed steel sheeting part. However, in this device the fiber guide conduit device can be fixed in a replaceable manner in a corresponding receiving bore of a prefabricated opening-cylinder housing. A seal of the fiber guide conduit device against the opening-cylinder housing is accomplished via an O-ring seal resting on the outer circumference of the fiber guide conduit device. This known fiber guide conduit device is sealed against the conduit plate by a hose nozzle.
It has been experienced in practice that sealing problems occur with such steel sheet constructions which do not permit an orderly spinning operation.
Moreover, bipartite fiber guide conduit devices are known, e.g. from German Patent Publications DE 29 47 294 A1 and DE 39 23 060 A1 in which the fiber entry area of the fiber guide conduit device is displaceably mounted in the opening-cylinder housing. The movable arrangement of one of the fiber guide conduit parts is intended to assure a reliable seal between the two fiber guide conduit sections. However, this known patent literature does not explain how these movable fiber guide conduit parts are manufactured.